The invention relates to a self-emptying clarifying separator with foam-free removal of the clarified liquid by means of a paring disk mounted in a clarified liquid paring chamber, and an automatically operating system for sensing the solid level in the sludge chamber. The separator has one or more passages leading from the sludge chamber to a lower, auxiliary paring chamber, and two auxiliary paring disks of different diameters, the first of which is disposed in the lower, auxiliary paring chamber and the second in the clarified liquid paring chamber. The paring passages of the first and second auxiliary paring disk are communicated with each other by a passageway having mounted therein a flow monitoring means located outside of the separator.
A clarifying separator of this kind is known, for example, from German Gebrauchsmuster No. 7,228,257. In this known separator, the second auxiliary paring disk disposed in the upper, clarified liquid paring chamber has a slightly greater diameter than the first auxiliary paring disk which is disposed in the lower, auxiliary paring chamber. Thus, a small portion of the clarified liquid is pumped by the larger auxiliary paring disk from the upper clarified liquid paring chamber through the flow monitor means located outside of the separator and through the passage from the monitor means to the smaller auxiliary paring disk, into the lower auxiliary paring chamber from which it flows through passages into the sludge chamber of the separator.
These passages are formed partially of bores and partially of segment-shaped chambers separated from one another by ribs. In other designs they consist mostly of individual tubes. As soon as the solids removed by centrifugal force cover the discharge orifices of these passages, the free liquid level in the lower paring chamber shifts inwardly. As a result of the increasing depth of immersion of the first paring disk, which is mounted in the lower paring chamber, the counterpressure acting on the flow monitor is increased, so that the flow diminishes. This decrease of the flow is utilized for the purpose of supplying to a control apparatus the starting pulse for the initiation of the ejection of the solids.
In the known separator, the liquid which senses the level of the solids is introduced into the sludge chamber from the lower paring chamber. As the discharge orifices of the passages begin to be covered by spun-out solids and as the free liquid level in the lower paring chamber begins to shift as a result thereof, the outwardly directed liquid pressure on the discharge orifices of the passages also increases. In the case of fine solids having a tendency to swirl up, the orifices of the passages are flushed repeatedly clear by the increasing liquid pressure, so that a firm plug of solids cannot form. The result is that the system for starting the ejection of the solids does not respond.
When the separator is charged with a cleaning solution, the way the flow operates is the same. Most of the solution is pumped out of the upper paring chamber by the discharge or clarified liquid paring disk, while a small portion is recirculated from the upper paring chamber through the flow monitor and the lower paring chamber into the separator. This is disadvantageous if the liquid that was centrifuged contained bacteria. Complete sterilization can then hardly be achieved on account of the constant recirculation.
Also, it is known, from German Pat. No. 1,145,100, for example, to remove liquid from the sludge chamber for the purpose of sensing the level of the solids, and combine it with the clarified liquid.